The invention relates to an optical system, and more particularly to an infrared lens arrangement having a high degree of compactness through employing at least three reflections, two of which are reflections of a collimated beam.
Infrared lens arrangements and detectors are known, but an unsatisfied need has been to provide a miniature, flyable sensor head for either target detection or target imaging in the infrared spectral region. Such a system must have great focal length and magnification and yet be fully contained in a small and compact package.